March 28, 1913.

THE COLLIERY GUARDIAN.

641

the group is nowhere visible ; while in South Stafford-
shire the top of the Keele beds is also unknown. In
Warwickshire, as a result of this work, it is now possible
for the first time to demonstrate the exact upward limit
of the Keele beds. The Warwickshire coalfield may
thus be regarded as the typical area of development of
the Upper coal measures of the Midland province, with
which the incomplete sequence exposed in other coalfields
can be compared.

One other fact of general interest clearly shown by
this correlation table is the remarkable attenuation of
consecutive subdivisions of the carboniferous system,
along a north-and-south line from Nottinghamshire
through Leicestershire to Warwickshire, just as there is
also an exactly similar attenuation on a parallel line
farther west through the North and South Staffordshire
coalfields. Further, this attenuation is accompanied by
the successive overlap of each subdivision upon the
pre-carboniferous floor of the district. This southerly
attenuation and overlap of the Lower carboniferous by
the Upper carboniferous, and also of the two lower
subdivisions of the Upper carboniferous, can be demon-
strated; and it may be inferred-that, in the unproved
area south of Coventry, the Middle coal measures in
turn thin away, and are overlapped by the barren Upper
coal measures. The southern margin of deposition of
the Middle coal measures must have lain along an
east-and-west line scmewhere to the south of Coventry;
therefore, we may conclude that the southern portion of
the basin wasj not depressed until late Middle coal-
measure times, and that the pre-carboniferous floor had
a general slope from south to north.

{To be continued.)

Grimsby Coal Exports.—The quantities of coal exported
from Grimsby for the week ended March 21 were : Foreign :
To Aarhus, 1,368 tons; Abus, 1,116; Antwerp, 482; Chris-
tiana, 1,506; Dieppe, 649; Esbjerg, 553; Gothenburg, 1,007;
Malmo, 530; Banders, 993; and Rotterdam, 447; total,
12,669 tons. No coal was ^shipped coastwise. The corre-
sponding week last year was the coal strike period, and the
foreign export was but 832 tons, while there was no coast-
wise shippings. In 1911 the totals for the corresponding
period were: Foreign, 22,500 tons, and coastwise, 2,287 tons.
For the week ended March 20 the following quantities were
exported from Immingham: Foreign: To Aalborg, 1,616;
Oxelosund, 4,310. Coastwise: To London, 3,210; total
foreign, 5,926 : total coastwise, 3,210 tons.

Coal Deliveries in Lancashire.—The question of means
for securing regular deliveries of coal, which is of vital
importance in the industrial districts of Lancashire, has
recently been engaging attention, and last week a deputa-
tion, representing the Oldham and District Coal Traders'
Association, the Oldham Chamber of Commerce, and the
Oldham Master Cotton Spinners' Association, waited upon
Mr. Marwood, one of the permanent secretaries of the
Board of Trade, for the purpose of laying their views before
that Department. Mr. William Barton, M.P., introduced
the deputation.—Mr. George Booth, one of the represen-
tatives of the coal traders, drew attention to a dispute
which he said had occurred between railway companies, the
effect of which had been that wagons were stopped for a
matter of four or five days. In consequence of that the
pits were unable to get through empties, and it was a fact
that some mills in Oldham were within 12 hours of stopping
through want of coal. Had they been stopped, between
20,000 and 30,000 workpeople would have been rendered
idle. Mr. Booth pointed to the seriousness of such
delays.—Mr. A. Taylor, another representative of the
coal traders, instanced a case in which a number of wagons
had taken eight to 10 days to do the single journey to
one colliery. About 150 wagons had for a considerable
period been doing only about 27 journeys per year, whereas
20 years ago they expected 100 journeys per year from the
same class of wagon. That meant a great waste of time,
because the railway companies had to deal with more
wagons[and were blocking their own lines, while not bring-
ing them through quicker. If they as traders had any
cause of complaint they did not seem to have any redress,
except through the Bail way and Canal Commissioners, which
was a very expensive method.—An interesting subject was
brought forward by Mr. S. E. Taylor, who said that the last
Weights and Measures Act contained a clause to the effect
that a railway wagon was not a vehicle in the sense of the
Act. Bailway companies and colliery companies, therefore,
would not be liable to be called upon to have their wagons
tested, and he declared that there were some collieries from
which the weight invoice could not be obtained from the
top of the pits. He asked if the Board of Trade could not
do something to put the companies under the Weights and
Measures Act, as the merchants were, or bring in some
other short Act to make them liable to penalty if they did
not get the weight invoiced.—Other speakers addressed
themselves to the question of delays as they affect the
manufacturers in Oldham, and Mr. Marwood, in reply, said
that although the powers of the Board of Trade were
limited he felt he could say that they would exercise all the
powers they could to prevent a recurrence of the delays.

SOUTH WALES INSTITUTE OF ENGINEERS.

Annual Meeting.

The fifty-fifth annual general meeting of the South
Wales Institute of Engineers took place at the Royal
Institution of South Wales, Swansea, on Tuesday,
March 18, 1913, the chair being occupied by Mr. John
Roberts, a vice-president.

On the motion of Mr. David E. Roberts, M.Inst.C.E.,
the report of the council and the statement of accounts
for the session ended December 31, 1912, were adopted.

The following gentlemen were elected to the
institute.-—Mr. F. M. Birks, Swansea; Mr. John
Cameron, locomotive superintendent, Taff Vale Rail-
way; Mr. W. E. Jayne, Aberdare; Mr. J. W. Jordan,
Bedwas, Mon.; Mr. C. M. Kitto, New Tredegar; Mr.
H. D. Madden, Cardiff ; Mr. T. E. Salter, Ystradgynlais;
and Mr. W. H. Williams, Penarth. Mr. H. D.
Griffiths, Griffithstown, Mon., was elected an associate
member; and the following were admitted as student-
members :—Messrs. A. S. Harding, Abertillery; T. P.
Morgan, Nelson, near Cardiff; and W. J. Smith,
Aberbeeg, Mon.

Lewis Prizes for 1913 Session.

The council announced that the subject selected for
this year’s competition for Lewis prizes of £25 and £10
was—“ The Most Approved Methods of Hauling the
Coal from the Working Faces to the Pit Bottom.”

The Tin-plate Trade : Some Recent Developments.

Mr. H. Spence Thomas, Cardiff, read a paper on this
subject, and afterwards displayed some slides on the
screen, the features of which were pointed out by Mr.
R. P. Bevan, Briton Ferry.

The author remarked that the very first paper read
before the institute at its first open meeting in January
1858 was upon the tin-plate trade by Mr. Ebenezer
Rogers, of Abercarn, and since that date no contribution
on the subject to the institute’s Proceedings had been
made until that day. The tin-plate trade was one upon
which there was but very little literature ; whilst on the
purely technical side there were practically no records;
hence a difficulty arises in making a comparison except
within the knowledge of one’s own time.

The manufacture of a tin-plate from the time the steel
bar was received at the works until the finished tin-plate
was complete, packed ready for shipment, practically
occupied a week. The plate went through seven depart,
ments, and was kept there the approximate time set
opposite each :—(1) Mills, 24 hours ; (2) black pickling
| hour; (3) black annealing and cooling, 74 hours.
(4) cold rolls, J hour; (5) white annealing and cooling,
58 hours ; (6) white pickling, % hour; (7) tinning,
assorting and packing, | hour—total, 158 hours.

In the engineering side of the tin-plate works there
had been great development in order to deal with the
stronger and heavier machinery which called for repairs
from time to time. For example, the rolls of the tin-
house were now over 7 ft. long, as against 3 ft. 25 years
ago. The author then dealt with several recent improve-
ments in engineering equipment. Twenty-five years ago
the common size of the mill rolls was 26 in. long by
18 J in. diameter, with 13|> in. diameter necks, but to-day
28 in. by 21 in. diameter, with 16 in. diameter necks, was
quite common in tin mills, whilst at least one works
were running some of their tin-mill rolls 28 in. long by

24	in. diameter, with 18 in. diameter necks. The steel
bars were 6Jin. wide and a “piece” weighed 271b.

25	years ago, whilst to-day the bars were generally 9 in,
wide and the “ piece ” often weighed 35 lb. Practically
no lighter substance than common was produced (except
taggers) before the McKinley Tariff; but to-day
“ light ” plates were the vogue, and the workmen were
paid on the same scale for them as if the heavier weight
was handled.

There had been no alteration in the mill furnaces in
shape, whilst there was a great diversion of practice
between different works as to the material of which the
hearths of the furnaces were made. Some works went
in for brick bottoms, plain or corrugated, others for
cast iron, whilst many preferred to have the hearth
made of ordinary coals. Producer gas-fired furnaces
had been tried at works in the Briton Ferry and
Pontardulais districts, but the advantages had not been
always sufficient to justify their retention. Gas furnaces
on the regenerative plan also had been put in one of the
Swansea works, and were now working. Gas-fired
furnaces had, however, not found general favour in
English practice. In English mills only about 25 per
cent, of the effective rolling capacity of the mill was
utilised, and where a sufficiency of engine power and
suitable plant existed the output in England could very
well be doubled by double manning the mills, as in
America, and still leave a margin of 50 per cent.

Mr. Thomas next dealt with various types of engines
employed in driving mills. As regards steam plant, he

mentioned that several of the later plants had had
their engines built on a system of steam expansion in
one cylinder, having an annular exhaust chamber in the
middle of the cylinder, generally known as the Uni-flow
type. Many doubts were expressed as to the practical
and economic results; but apparently the users were
satisfied, as they had given repeat orders. Lately at
Swansea there has been laid down a fine electric installa-
tion having 12 mills driven by three motors. The
whole of the current for the works was generated by
steam on the spot, and it was said to be a part of a huge
scheme of blastfurnaces and steelworks. There was a
works in the Llanelly area driven entirely by electricity
supplied by the local power company. At only one
works had a gas engine been put to drive tin-plate mills,
and this was an engine of 350-horse power running at
170 revolutions per minute, driving by means of ropes
on to the flywheel running about 40 revolutions per
minute. Two mills were driven by this engine, and no
difficulty was experienced so far as the mechanical side
was concerned ; but it is said that owing to using coal
containing very large quantities of tarry matters, and
with an insufficiency of apparatus to eliminate the tar
from the gas, the valves of the engine become clogged
by this tar, so stopping the engine. If the tar trouble
could be overcome, there was no reason why this drive
should not be an economical one under favourable
conditions.

The paper next dealt in succession with “black
pickling,” “ black annealing,” “ cold rolling,” “ white
annealing,” “ white pickling,” and the processes carried
on in the tinhouse. To-day, it was stated, the con-
sumption of tin per box of tin-plates, whilst kept a
profound secret, probably varied but little as between
one works and another, whereas 25 years ago the
differences were great. A quarter of a century ago
some works were consuming almost as low as 2 lb. of
tin per standard box of tin-plates, but it was with a
degree of regret that one was forced to admit that
to-day, after 25 years of endeavour, there is but very
little, or at all events insufficient improvement in this
respect. Steel plates had been coated with tin by
means of electricity, but only in an experimental stage•
A beginning had been made in the Swansea district to
coat black-plates with the metal of aluminium (it is
said by a cold wet electric process), and it was early yet
to state whether they would grow into general use.

In conclusion the author suggested that if standardi-
sation could be agreed upon by the trade, a very large
economy would be effected. Possibly a committee
formed on the same lines as the existing Engineering
Standards Committee could take these matters in hand,
and probably the Tin-plate Makers’ Association might
feel inclined to take the subject up. The microscope,
so largely used in steelmaking, and other great
industries, was practically absent from the trade. Again
the pyrometer was almost unknown in the English tin-
plate trade, though beneficial results were being obtained
by one works. There is so much of an apparently
mysterious nature that was unknown in regard to the
tin-plate trade, and the factors governing the consump-
tion of tin, ‘sthat one would like to see some of the
younger generation, who have had the benefit of a
scientific training, devote their time and energy in the
direction of systematically investigating these matters,
with a free use of both microscope and pyrometer. The
following ideas occurred to nearly every tin-plate works*
manager as worthy of research :—(1) The result of hot
and cold rolling in the mills; (2) the result of a high
peripheral roll speed in the mills; (3) the boshing and
non-boshing of the iron in the mills ; (4) over and under
black pickling, and influence of strength and tempera-
ture of the acid solution, also of time; (5) effect of
varying temperatures and time of annealing; (6) light
and heavy cold rolling; (7) temperature effects in the
tinning operations; (8) differences from the tin-plate
trade point of view between—acid Bessemer steel,
basic Bessemer steel, acid open-hearth steel, basic open-
hearth steel, and the comparative tin consumption for
each kind. To several has occurred the idea of the
establishment of an office which would probably incor-
porate some of the present tin-plate samples, into a
kind of Lloyds’ Proofing House, "whose certificate as
regards the quality, condition, sheetage and weight of
the tin-plates should be accepted by all concerned, a
clause embodying this as a condition to be inserted in
all tin-plate contract notes. This would be welcomed by
most buyers and sellers, and would avoid many causes
of friction in the merchanting of the cheapest finished,
article in the world.

There was at the present time considerable develop-
ment in the tin-plate trade abroad, particularly on the
Continent of Europe; existing works were extending,
while a number of schemes are projected. In one
works, which have already 15 mills, they were putting